net/netfilter/nft_counter.c

   1 /*
   2  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Development of this code funded by Astaro AG (http://www.astaro.com/)
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/seqlock.h>
  15 #include <linux/netlink.h>
  16 #include <linux/netfilter.h>
  17 #include <linux/netfilter/nf_tables.h>
  18 #include <net/netfilter/nf_tables.h>
  19
  20 struct nft_counter {
  21         s64             bytes;
  22         s64             packets;
  23 };
  24
  25 struct nft_counter_percpu_priv {
  26         struct nft_counter __percpu *counter;
  27 };
  28
  29 static DEFINE_PER_CPU(seqcount_t, nft_counter_seq);
  30
  31 static inline void nft_counter_do_eval(struct nft_counter_percpu_priv *priv,
  32                                        struct nft_regs *regs,
  33                                        const struct nft_pktinfo *pkt)
  34 {
  35         struct nft_counter *this_cpu;
  36         seqcount_t *myseq;
  37
  38         local_bh_disable();
  39         this_cpu = this_cpu_ptr(priv->counter);
  40         myseq = this_cpu_ptr(&nft_counter_seq);
  41
  42         write_seqcount_begin(myseq);
  43
  44         this_cpu->bytes += pkt->skb->len;
  45         this_cpu->packets++;
  46
  47         write_seqcount_end(myseq);
  48         local_bh_enable();
  49 }
  50
  51 static inline void nft_counter_obj_eval(struct nft_object *obj,
  52                                         struct nft_regs *regs,
  53                                         const struct nft_pktinfo *pkt)
  54 {
  55         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  56
  57         nft_counter_do_eval(priv, regs, pkt);
  58 }
  59
  60 static int nft_counter_do_init(const struct nlattr * const tb[],
  61                                struct nft_counter_percpu_priv *priv)
  62 {
  63         struct nft_counter __percpu *cpu_stats;
  64         struct nft_counter *this_cpu;
  65
  66         cpu_stats = alloc_percpu(struct nft_counter);
  67         if (cpu_stats == NULL)
  68                 return -ENOMEM;
  69
  70         preempt_disable();
  71         this_cpu = this_cpu_ptr(cpu_stats);
  72         if (tb[NFTA_COUNTER_PACKETS]) {
  73                 this_cpu->packets =
  74                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_PACKETS]));
  75         }
  76         if (tb[NFTA_COUNTER_BYTES]) {
  77                 this_cpu->bytes =
  78                         be64_to_cpu(nla_get_be64(tb[NFTA_COUNTER_BYTES]));
  79         }
  80         preempt_enable();
  81         priv->counter = cpu_stats;
  82         return 0;
  83 }
  84
  85 static int nft_counter_obj_init(const struct nft_ctx *ctx,
  86                                 const struct nlattr * const tb[],
  87                                 struct nft_object *obj)
  88 {
  89         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
  90
  91         return nft_counter_do_init(tb, priv);
  92 }
  93
  94 static void nft_counter_do_destroy(struct nft_counter_percpu_priv *priv)
  95 {
  96         free_percpu(priv->counter);
  97 }
  98
  99 static void nft_counter_obj_destroy(struct nft_object *obj)
 100 {
 101         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 102
 103         nft_counter_do_destroy(priv);
 104 }
 105
 106 static void nft_counter_reset(struct nft_counter_percpu_priv __percpu *priv,
 107                               struct nft_counter *total)
 108 {
 109         struct nft_counter *this_cpu;
 110
 111         local_bh_disable();
 112         this_cpu = this_cpu_ptr(priv->counter);
 113         this_cpu->packets -= total->packets;
 114         this_cpu->bytes -= total->bytes;
 115         local_bh_enable();
 116 }
 117
 118 static void nft_counter_fetch(struct nft_counter_percpu_priv *priv,
 119                               struct nft_counter *total)
 120 {
 121         struct nft_counter *this_cpu;
 122         const seqcount_t *myseq;
 123         u64 bytes, packets;
 124         unsigned int seq;
 125         int cpu;
 126
 127         memset(total, 0, sizeof(*total));
 128         for_each_possible_cpu(cpu) {
 129                 myseq = per_cpu_ptr(&nft_counter_seq, cpu);
 130                 this_cpu = per_cpu_ptr(priv->counter, cpu);
 131                 do {
 132                         seq     = read_seqcount_begin(myseq);
 133                         bytes   = this_cpu->bytes;
 134                         packets = this_cpu->packets;
 135                 } while (read_seqcount_retry(myseq, seq));
 136
 137                 total->bytes    += bytes;
 138                 total->packets  += packets;
 139         }
 140 }
 141
 142 static int nft_counter_do_dump(struct sk_buff *skb,
 143                                struct nft_counter_percpu_priv *priv,
 144                                bool reset)
 145 {
 146         struct nft_counter total;
 147
 148         nft_counter_fetch(priv, &total);
 149
 150         if (nla_put_be64(skb, NFTA_COUNTER_BYTES, cpu_to_be64(total.bytes),
 151                          NFTA_COUNTER_PAD) ||
 152             nla_put_be64(skb, NFTA_COUNTER_PACKETS, cpu_to_be64(total.packets),
 153                          NFTA_COUNTER_PAD))
 154                 goto nla_put_failure;
 155
 156         if (reset)
 157                 nft_counter_reset(priv, &total);
 158
 159         return 0;
 160
 161 nla_put_failure:
 162         return -1;
 163 }
 164
 165 static int nft_counter_obj_dump(struct sk_buff *skb,
 166                                 struct nft_object *obj, bool reset)
 167 {
 168         struct nft_counter_percpu_priv *priv = nft_obj_data(obj);
 169
 170         return nft_counter_do_dump(skb, priv, reset);
 171 }
 172
 173 static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
 174         [NFTA_COUNTER_PACKETS]  = { .type = NLA_U64 },
 175         [NFTA_COUNTER_BYTES]    = { .type = NLA_U64 },
 176 };
 177
 178 static struct nft_object_type nft_counter_obj __read_mostly = {
 179         .type           = NFT_OBJECT_COUNTER,
 180         .size           = sizeof(struct nft_counter_percpu_priv),
 181         .maxattr        = NFTA_COUNTER_MAX,
 182         .policy         = nft_counter_policy,
 183         .eval           = nft_counter_obj_eval,
 184         .init           = nft_counter_obj_init,
 185         .destroy        = nft_counter_obj_destroy,
 186         .dump           = nft_counter_obj_dump,
 187         .owner          = THIS_MODULE,
 188 };
 189
 190 static void nft_counter_eval(const struct nft_expr *expr,
 191                              struct nft_regs *regs,
 192                              const struct nft_pktinfo *pkt)
 193 {
 194         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 195
 196         nft_counter_do_eval(priv, regs, pkt);
 197 }
 198
 199 static int nft_counter_dump(struct sk_buff *skb, const struct nft_expr *expr)
 200 {
 201         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 202
 203         return nft_counter_do_dump(skb, priv, false);
 204 }
 205
 206 static int nft_counter_init(const struct nft_ctx *ctx,
 207                             const struct nft_expr *expr,
 208                             const struct nlattr * const tb[])
 209 {
 210         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 211
 212         return nft_counter_do_init(tb, priv);
 213 }
 214
 215 static void nft_counter_destroy(const struct nft_ctx *ctx,
 216                                 const struct nft_expr *expr)
 217 {
 218         struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 219
 220         nft_counter_do_destroy(priv);
 221 }
 222
 223 static int nft_counter_clone(struct nft_expr *dst, const struct nft_expr *src)
 224 {
 225         struct nft_counter_percpu_priv *priv = nft_expr_priv(src);
 226         struct nft_counter_percpu_priv *priv_clone = nft_expr_priv(dst);
 227         struct nft_counter __percpu *cpu_stats;
 228         struct nft_counter *this_cpu;
 229         struct nft_counter total;
 230
 231         nft_counter_fetch(priv, &total);
 232
 233         cpu_stats = alloc_percpu_gfp(struct nft_counter, GFP_ATOMIC);
 234         if (cpu_stats == NULL)
 235                 return -ENOMEM;
 236
 237         preempt_disable();
 238         this_cpu = this_cpu_ptr(cpu_stats);
 239         this_cpu->packets = total.packets;
 240         this_cpu->bytes = total.bytes;
 241         preempt_enable();
 242
 243         priv_clone->counter = cpu_stats;
 244         return 0;
 245 }
 246
 247 static struct nft_expr_type nft_counter_type;
 248 static const struct nft_expr_ops nft_counter_ops = {
 249         .type           = &nft_counter_type,
 250         .size           = NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
 251         .eval           = nft_counter_eval,
 252         .init           = nft_counter_init,
 253         .destroy        = nft_counter_destroy,
 254         .dump           = nft_counter_dump,
 255         .clone          = nft_counter_clone,
 256 };
 257
 258 static struct nft_expr_type nft_counter_type __read_mostly = {
 259         .name           = "counter",
 260         .ops            = &nft_counter_ops,
 261         .policy         = nft_counter_policy,
 262         .maxattr        = NFTA_COUNTER_MAX,
 263         .flags          = NFT_EXPR_STATEFUL,
 264         .owner          = THIS_MODULE,
 265 };
 266
 267 static int __init nft_counter_module_init(void)
 268 {
 269         int cpu, err;
 270
 271         for_each_possible_cpu(cpu)
 272                 seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
 273
 274         err = nft_register_obj(&nft_counter_obj);
 275         if (err < 0)
 276                 return err;
 277
 278         err = nft_register_expr(&nft_counter_type);
 279         if (err < 0)
 280                 goto err1;
 281
 282         return 0;
 283 err1:
 284         nft_unregister_obj(&nft_counter_obj);
 285         return err;
 286 }
 287
 288 static void __exit nft_counter_module_exit(void)
 289 {
 290         nft_unregister_expr(&nft_counter_type);
 291         nft_unregister_obj(&nft_counter_obj);
 292 }
 293
 294 module_init(nft_counter_module_init);
 295 module_exit(nft_counter_module_exit);
 296
 297 MODULE_LICENSE("GPL");
 298 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
 299 MODULE_ALIAS_NFT_EXPR("counter");
 300 MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_COUNTER);